Effectiveness of regionally-specific immunotherapy for the management of canine atopic dermatitis.

BACKGROUND: Canine atopic dermatitis is a common pruritic skin disease often treated with allergen immunotherapy (AIT). AIT in dogs traditionally begins with attempting to identify clinically relevant environmental allergens. Current allergen testing methodologies and immunotherapy techniques in dogs are not standardized. Immunotherapy with a mixture of allergenic extracts selected based on regional aerobiology rather than intradermal tests or serum IgE assays has been described. The objective of this study was to evaluate the effectiveness of regionally-specific immunotherapy in dogs with atopic dermatitis. The medical records of a veterinary dermatology referral clinic were searched for dogs with atopic dermatitis that began regionally-specific subcutaneous immunotherapy from June, 2010 to May, 2013. An overall assessment of treatment effectiveness (excellent, good, fair, or poor) was assigned based upon changes in pruritus severity, lesion severity, and the reduction in concurrent medication(s) during a follow-up period of at least 270 days. Baseline characteristics that might predict treatment success were analyzed with the Spearman's correlation and the Kruskal-Wallis tests. RESULTS: Of the 286 dogs that began regionally-specific immunotherapy (RESPIT) during a 3 year period, 103 met the inclusion criteria. The overall response to RESPIT was classified as excellent in 19%, good in 38%, fair in 25%, and poor in 18% of dogs. The response classification correlated significantly with a reduction in pruritus severity (r = 0.72, p < 0.001) and lesion severity (r = 0.54, p < 0.001), but not with the dogs' baseline characteristics. Adverse reactions were reported in 7/286 (2.4%) of treated dogs. CONCLUSIONS: Under the conditions of this study, RESPIT was safe and effective for the treatment of atopic dermatitis in dogs.

Acute neurokinin-1 receptor antagonism fails to dampen airflow limitation or airway eosinophilia in an experimental model of feline asthma.

OBJECTIVES: Feline allergic asthma is a chronic inflammatory disorder of the lower airways that may manifest with acute, life-threatening clinical signs. Tachykinins released from sensory nerves and immune cells binding neurokinin (NK)-1, NK-2 and NK-3 receptors have been implicated in asthma pathogenesis. Maropitant, an NK-1 receptor antagonist, blocks neuroimmune pathways and may be a viable treatment option for cats in asthmatic crisis. Using an experimental chronic allergic feline asthma model, we hypothesized that a single dose of maropitant given immediately after allergen challenge would blunt clinical signs, airway hyperresponsiveness (AHR) and airway eosinophilia. METHODS: Cats (n = 7) induced to have an asthmatic phenotype using Bermuda grass allergen (BGA) were enrolled in a prospective, placebo-controlled crossover design study. Cats randomly received maropitant (2 mg/kg SC) or placebo (saline SC) immediately post-BGA challenge, followed 12 h later by pulmonary mechanics testing and measurement of airway eosinophils. After a 2 week washout, cats were crossed-over to the alternate treatment. Study endpoints included subjective clinical scoring systems post-BGA challenge, ventilator-acquired pulmonary mechanics to assess AHR after bronchoprovocation with methacholine and collection of bronchoalveolar lavage fluid to quantify airway eosinophilia. Data were analyzed using a Mann-Whitney rank sum test with P <0.05 considered significant. RESULTS: A single injection of maropitant failed to diminish clinical composite score (P = 0.902), visual analogue scale scoring (P = 0.710), AHR (P = 0.456) or airway eosinophilia (P = 0.165) compared with placebo. CONCLUSIONS AND RELEVANCE: A single injection of maropitant given immediately post-allergen challenge was ineffective at blunting clinical signs, AHR and airway eosinophilia, and cannot be recommended as treatment for feline status asthmaticus.

Feline vaccination practices and protocols used by veterinarians in the United Kingdom.

Vaccination is an important aspect of disease control in the feline population, as it prevents disease or reduces its severity in individual cats. However the types of antigens that should be administered to cats, the frequency of administration of certain antigens and the anatomical location at which vaccines should be administered are controversial. Various groups have developed guidelines to help veterinarians decide vaccine protocols for cats in their care. The aim of this study was to survey veterinarians in the United Kingdom about the vaccination protocols used in 2007-2008. A questionnaire about aspects of feline vaccination was distributed to a 431 veterinary practices taking part in a case-control study of feline injection site sarcomas. A response rate of 72% was achieved. The majority of veterinarians who responded administered the commonly used antigens annually (84-96% of practices). Most of the veterinarians administered most vaccines in the interscapular region (90-96% of practices depending on the antigen). The vaccination practices of the veterinarians were not consistent with the published vaccination guidelines at that time.

Beneficial cross-protection of allergen-specific immunotherapy on airway eosinophilia using unrelated or a partial repertoire of allergen(s) implicated in experimental feline asthma.

The study hypothesis was that in experimentally asthmatic cats rush immunotherapy (RIT) using allergens not completely matched with sensitizing allergen(s) would at least partially attenuate the asthmatic phenotype and modulate the aberrant immune response. In phase I, cats sensitized to Bermuda grass allergen (BGA), house dust mite allergen (HDMA) or placebo received BGA RIT. In phase II, cats dually sensitized to BGA and HDMA received RIT using BGA, HDMA or placebo. Efficacy of RIT was assessed using percentage bronchoalveolar lavage fluid (BALF) eosinophils. Additionally, a variety of immunologic assays were performed. Eosinophilic airway inflammation significantly decreased over time in asthmatic cats given RIT using sensitizing allergen or unrelated allergen (P<0.001). In dually sensitized cats, single allergen RIT but not placebo reduced airway eosinophilia (P=0.038). Differences in allergen-specific lymphocyte proliferation, in the number of IL-10 producing cells and in the percentage T regulatory cells were detected between asthmatic cats getting RIT and controls. Cross-protection manifested by reduced airway eosinophilia was noted in cats treated with RIT allergens which did not completely match allergen used in asthma induction. However, the mechanism of immunologic tolerance may differ when improperly matched allergens to the sensitizing allergens are used in RIT.

Feline vaccination protocols: is a consensus emerging?

Three international panels have been established over the past 11 years to provide veterinarians with guidelines on the use of feline vaccines. These are the American Association of Feline Practitioners (AAFP) Feline Vaccine Advisory Panel, the World Small Animal Association Vaccine Guidelines Group (WSAVA VGG) and the European Advisory Board on Cat Diseases (ABCD). The major recommendations of these three panels are summarised to show areas of agreement and areas of discrepancy. While the recommendations of the three groups are not fully aligned, all agree that core vaccines (those that every cat should receive) include panleucopenia virus (FPV), calicivirus (FCV) and herpesvirus (FHV-1) (with the addition of rabies virus where it is endemic or mandated by law). All the panels also recommend booster vaccination for the three core vaccines at intervals of more than one year in many situations (up to every three years for FCV and FHV-1 after the first booster, and at intervals no more frequently than every three years for FPV after the first booster), in view of the studies evaluating the duration of immunity for these vaccines. Precise recommendations vary though, and further studies are needed to provide additional information to clarify areas of discrepancy and further refine recommendations for the future. Ultimately the aim should be to vaccinate cats less frequently (based on a knowledge of the true duration of immunity conferred by vaccination), but to vaccinate more cats (and ideally every cat).

Protection levels of vaccinated pigeons (Columba livia) against a highly pathogenic Newcastle disease virus strain.

The purposes of this study were to model a vaccination regimen for Newcastle disease virus (NDV) in pigeons, and to evaluate the susceptibility and behavior of vaccinated birds against a highly pathogenic NDV Brazilian strain. Antibody response was assessed by means of hemagglutination inhibition test (HI), and viral genome excretion by means of RT-PCR. Vaccinal strains (La Sota and Ulster) induced high antibody titers without any adverse effects, both in inoculated and in sentinel birds. A viral strain pathogenic for chickens did not produce clinical signs of the disease in experimentally infected pigeons. Only 4 out of 10 vaccinated pigeons shed NDV genome, and just for two days. Results confirmed the high infectivity of the vaccinal strains used, as all nonvaccinated pigeons showed antibody titers as high as those of vaccinated birds.

Dermatophagoides farinae-specific IgG responses in atopic dogs undergoing allergen-specific immunotherapy with aqueous vaccines.

The molecular and immunologic mechanisms associated with successful allergen-specific immunotherapy (ASIT) have not been completely elucidated. The aim of this study was to characterize the changes in Dermatophagoides farinae-specific IgG in atopic dogs undergoing ASIT using aqueous vaccines. Fifteen atopic dogs with a positive skin test reaction to D. farinae were treated with aqueous vaccines for a minimum of 2 months following a standard protocol. Serum samples were collected before and during therapy and used to probe Western blots containing separated proteins of D. farinae. IgG responses were detected using a polyclonal goat anticanine IgG antibody and a chromogenic substrate 3,3'-diaminobenzidine. The blots were analysed using a semiquantitative digital image analysis system that evaluated the number and molecular weight of bands, as well as their intensity, which was related to IgG concentration. Prior to ASIT, all dogs showed allergen-specific IgG responses to various antigens of D. farinae. During ASIT, there was a significant increase in the total quantity of D. farinae-specific IgG antibodies to various antigens from the mite (P = 0.015). Significant increases were observed for a 98-kDa band (P = 0.015), likely to be Der f 15; bands with molecular weights between 50 and 70kDa (P=0.012); and bands between 30 and 45 kDa (P = 0.035). These findings provide support for the hypothesis that ASIT induces IgG blocking antibodies to allergens known to be relevant in canine atopic dermatitis.

Evaluation of vaccination strategies against infection with feline immunodeficiency virus (FIV) based on recombinant viral vectors expressing FIV Rev and OrfA.

In recent years it has become clear that cell-mediated immunity is playing a role in the control of lentivirus infections. In particular, cytotoxic T lymphocyte responses have been associated with improved outcome of infection, especially those directed against the regulatory proteins like Rev and Tat, which are expressed early after infection. Therefore, there is considerable interest in lentiviral vaccine candidates that can induce these types of immune responses. In the present study, we describe the construction and characterisation of expression vectors based on recombinant Semliki Forest virus system and modified vaccinia virus Ankara for the expression of feline immunodeficiency virus (FIV) accessory proteins Rev and OrfA. These recombinant viral vectors were used to immunize cats using a prime-boost regimen and the protective efficacy of this vaccination strategy was assessed after challenge infection of immunized cats with FIV.

Bacterial quorum sensing: a new target for anti-infective immunotherapy.

BACKGROUND: Cell-to-cell communication via exchange of small molecules, 'autoinducers', is a widespread phenomenon among Gram-negative and -positive bacteria. This intercellular signaling that synchronizes population-wide gene expression in a cell-density-dependent manner is termed 'quorum sensing' (QS). The discovery that Gram-negative bacteria employ non-peptide structures, N-acyl homoserine lactones, to globally regulate production of secondary metabolites and proteins, initiated a new area of research. Subsequently, other quorum-sensing systems and small signaling molecules were identified. With the emergence of antibiotic-resistant bacteria, most prominently methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, new approaches for combating infections are needed. Inhibition of QS results in attenuation of virulence rather than direct killing of microbes. OBJECTIVE: We highlight current trends in preventing bacterial infections using quorum-quenching strategies. METHODS: We mainly focus on P. aeruginosa and S. aureus and their QS systems as targets for intervention. RESULTS/CONCLUSION: New research strongly suggests that QS systems represent attractive targets for discovery of novel anti-infective agents, including immunotherapeutic strategies.

Evaluation of a xenogeneic VEGF vaccine in dogs with soft tissue sarcoma.

Active immunization against pro-angiogenic growth factors or their receptors is an emerging strategy for controlling tumor growth and angiogenesis. Previous studies in rodent tumor models have indicated that immunization against xenogeneic growth factors is more likely to induce effective anti-tumor responses than immunization against the autologous growth factor. However, the effectiveness or safety of the xenogeneic vaccination approach has not been previously assessed in a clinically relevant outbred, spontaneous tumor model. Therefore, we investigated the safety and anti-tumor and anti-angiogenic effects of a xenogeneic vascular endothelial cell growth factor (VEGF) vaccine in pet dogs with spontaneous cancer. Nine dogs with soft tissue sarcoma were immunized with a recombinant human VEGF vaccine over a 16-week period. The effects of immunization on antibodies to human and canine VEGF, circulating VEGF concentrations, tumor microvessel density (MVD), and tumor growth were assessed. The xenogeneic VEGF vaccine was well-tolerated by all dogs and resulted in induction of humoral responses against both human and canine VEGF in animals that remained in the study long enough to receive multiple immunizations. Three of five multiply immunized dogs also experienced sustained decreases in circulating plasma VEGF concentrations and two dogs had a significant decrease in tumor MVD. The overall tumor response rate was 30% for all treated dogs in the study. We conclude therefore that a xenogeneic VEGF vaccine may be a safe and effective alternative means of controlling tumor growth and angiogenesis.

Immunogenicity of Trichophyton mentagrophytes isolated from arctic foxes with ringworm.

Immunogenicity of six strains of Trichophyton mentagrophytes var. granulosum isolated from arctic foxes with ringworm was evaluated in guinea pigs and foxes. Two strains of T. mentagrophytes (Tm-3 and Tm-4) out of six examined (Tm-1, Tm-2, Tm-3, Tm-4, Tm-5 and Tm-6) induced in the experimental foxes a strong cellular immune response measured by the leukocyte migration inhibition test (LMIT), lymphocyte transformation test (LTT), and by skin delayed-type hypersensitivity (DTH). The guinea pigs immunised with Tm-3 and Tm-4 were well protected against the artificial infection with the virulent strain of T. mentagrophytes (Tm-9). These two strains of T. mentagrophytes with high immunogenic properties were used for production of a vaccine against ringworm in foxes.

Immunization of broiler chicks by in ovo injection of infective stages of Eimeria.

Immunization of chickens by in ovo injection of infective stages of 5 species of Eimeria was investigated. Fertile Hubbard x Petersen broiler chicken eggs were injected through the air cell on d 18 of incubation with oocysts of E. acervulina, E. maxima, E. mitis, E. praecox, or E. brunetti. Injected doses of all species ranged from 1 x 10(2) to 1 x 10(6) sporulated oocysts per egg. Chicks receiving oocysts in ovo shed oocysts posthatch. After 2 wk in wire-floored cages, birds were given a challenge infection with the homologous Eimeria species. Chicks immunized by in ovo injection of oocysts had significantly reduced lesion scores, improved weight gain, or reduced oocyst output compared with their nonimmunized counterparts. In additional studies, eggs were injected with 1 x 10(5) sporozoites of E. tenella, E. maxima, or E. acervulina per egg. Sporozoites of E. acervulina were not infective for chick embryos when administered in phosphate-buffered saline, but if sporozoites were suspended in tissue culture medium when injected in ovo, hatched chicks shed oocysts with peak output occurring 3 to 4 d posthatch. Sporozoites of E. maxima and E. tenella were infective for 18-d-old embryos regardless of the vehicle. The results demonstrate that immunization of broiler chickens against several species of coccidia by in ovo injection of oocysts is feasible. The infectivity of sporozoites for 18-d-old chick embryos varied depending on the species of Eimeria and the vehicle in which the sporozoites were suspended prior to injection.

Effect of Cryptobia salmositica-induced anorexia on feeding behavior and immune response in juvenile rainbow trout Oncorhynchus mykiss.

At 10 degrees C, rainbow trout Oncorhynchus mykiss (n = 13 per group) infected with Cryptobia salmositica Katz, 1951 became anorexic at 3 wk post-infection (w.p.i.), with feed-intake decreasing significantly from 1.33 to 0.94% body weight (b.w.). Anorexia was most severe at 4 w.p.i. (0.80% b.w.), coinciding with peak parasitemia (9.2 x 10(6) parasites ml blood(-1)) and anemia. At 8 w.p.i., fish had recovered their appetite although they still had contained detectable parasites (6.8 x 10(5) parasites ml(-1)) and were anemic (pack cell volume, PCV, of 24.4%). However at 5 degrees C, anorexia occurred at 5 w.p.i. (0.81% b.w.), and was most severe at 7 w.p.i. (0.40% b.w.). At 8 w.p.i. (0.43% b.w.), fish displayed high parasitemia (4.6 x 10(6) parasites ml(-1)) and low PCV (10.8%). Fish at 5 degrees C had lower gastric evacuation (GE) rates (GE48h) than 10 degrees C fish, however there were no differences between infected and naive fish at both temperatures. Before anorexia, there was no significant correlation between mean share of meal (MSM, a measure of how food was partitioned within a group) and coefficient of variation in feeding but this became significant during anorexia (p = 0.02 and p = 0.0002 at 10 and 5 degrees C respectively). Significant correlations were detected between b.w. and MSM before onset of anorexia at 10 degrees C (p = 0.005) and 5 degrees C (p = 0.02); this was maintained at 10 degrees C (p = 0.001) but not at 5 degrees C (p = 0.98). Fish on an anorexic diet (0.93% b.w.) responded well at 10 degrees C to a live C. salmositica vaccine; this could partly be due to constant antigenic stimulation by the live vaccine.

Immune therapy in respiratory disease.

Pharmacologic manipulation of pulmonary immunity plays an important role in primary and adjunct therapy for equine respiratory disease. Frequent exposure to respiratory viral pathogens, strenuous exercise, long distance transport, and inhalation of harmful substances destroy various aspects of the pulmonary defense system and predispose performance horses to development of infectious and noninfectious respiratory disease. Pulmonary immunity may be bolstered by nonspecific immunostimulants to combat primary or secondary immunodeficiency. State of the art technology improves active and passive-specific immunity for prevention of common infectious respiratory diseases in horses. Immuno-suppressive therapy can attenuate hyperreactive pulmonary immune responses in horses with allergic airway disease.

Critical features of veterinary field trials.

The field trials of drug and vaccine efficacy published in The Veterinary Record in the last five years were reviewed. The reviewers showed that in addition to some excellent studies with clear and concise design and analysis, there was a considerable lack of detail in reporting the method of allocation of animals to treatments, whether groups of animals or individual animals were allocated to treatments, whether the trials were blind, and a lack of formal analysis of the results. A considerable number of studies had problems with clustering of data. Some critical features of the design and analysis of a clinical field trial are discussed and improvements are proposed.

Immunotherapy of periocular squamous cell carcinoma with metastasis in a pony.

A 5-year-old Pony of America mare was referred for evaluation of inflamed upper and lower right eyelids. Squamous cell carcinoma of the eyelids and ulcerative keratitis secondary to self-trauma were diagnosed. Initial treatment of the eyelid neoplasia with 2 applications of cryotherapy failed to resolve the lesions, and immunotherapy with bacillus of Calmette-Guerin (BCG) was instituted. Multiple injections of BCG over a 17-week period resulted in progressive shrinkage of the tumor mass, but regional metastasis to the ipsilateral submandibular lymph node occurred. Six months later, ocular neoplastic lesions were not evident, and the lymph node had regressed in size. Eighteen months after the diagnosis of metastatic disease, signs of recurrence were not noticed in either the primary or secondary tumor sites. Squamous cell carcinoma of the equine eyelid historically carries a poor prognosis for resolution. Immunotherapy for equine ocular squamous cell carcinoma should be considered as a treatment alternative to cryosurgery, radiotherapy, hyperthermy, and CO2 laser ablation, especially in cases involving the eyelid.

An inactivated vaccine against ringworm.

A new vaccine against ringworm, containing the inactivated Trichophyton verrucosum strain, was assessed on guinea pigs and calves under experimental conditions and on three herds of cattle under natural conditions. The vaccine elicited a distinct immune response of the cellular type. This type of immunity assessed by the migration inhibition test of leukocytes corresponded to the immunity evaluated by the challenge. In herds in which there were from 30 to 67% of naturally infected animals with T. verrucosum, two doses of the vaccine resulted in after 4 weeks a decrease of the number of animals with clinical changes from 40.5 to 100% depending on the group of animals under study.

Therapeutic value of partial excision of lesions combined with administration of an autogenous vaccine during an episode of cutaneous papillomatosis in cattle of Uganda.

The therapeutic value of partial excision of lesions combined with administration of an autogenous vaccine in calves during an episode of cutaneous papillomatosis was evaluated. Of 10 Holstein calves naturally infected with cutaneous papillomatosis, 5 were given 20 ml of autogenous vaccine in addition to undergoing partial excision of the lesions; the other 5 calves were not given vaccine. Results indicate that partial excision combined with administration of autogenous vaccine has some therapeutic value in calves with small pedunculated papillomas, but not in calves with large confluent lesions.